Process of manufacturing vulcanized rubber and product thereof



I PROCESS OF MANUFACTURII TG VULCAN Patented Oct. 23, 1928.

UNITED STATES- -WINFIELiD SCOTT, F AKRON, QHIO, ASSIGNOR T0 7 TORIES COMPANY, OF AKRON, OHIQ,

M No Drawing.-

- The present invention relates to the process ofmanufacturing a vulcanized rubber prodnot by employing a dissimilar-aryl di-sub stitute'd-guanidine as an accelerator of'that' process. The invention will be understood from the following description and examples wherein the invention is fully set forth and described as rubber vulcanization accelerators I have found, however, that as aclass, all symmetrical and dissimilar-aryl didescribed.

Diphenyl-guanidine and other 'similarly' constituted guanidines have heretofore been substituted-guanidines are not accelerators of the vulcanization process, and furthermore that many of the compounds of this class that do accelerate theprocess mentioned, are not suficiently active as to be commercially practicableufor use in this process.

' Thenature and type of the radical introduced into the guanldine nucleus generally has a profound effect upon the vulcanization accelerating properties of the resulting com; pound.- .Many of the di-substituted-guan-' The, thiourea so obtained was then desulphurized by treatment with a leadcompound while warming under pressure in the presence of a'mmonia. "Preferably the am- 'monia was used in theformiof an alcoholic solution thereof. The heating of the mass was continued for a period of time necessary to produce. substantially complete combina- 'tion of the substances whereupon the mixture was allowed to cool, any excess of pressure was released, and the reaction product was filtered. The residuum was then washed with a diluted acid such as hydrochloric acid to dissolve any guani'dine derivative from un-' oil withpamino-'di-methyl-aniline to dupe ajthiourea and then desulphurizing the thiourea so formed.

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a licatio filed A rn s, 192a Serial No. 182,187.

idines'are non-accelerators, some ,are' faster in the r action in a rubber'sulphur mix than is -di-phenyl-guanidine, several are sub stantially the same in accelerating power, and others have their accelerating value so imfrom an accelerating standpoint.

v One dissimilar-aryl substituted di-phenyli.

guanidine which I,

the properties of which I have investigated as an accelerator of therubber vulcaniza-- tion process is p-di-methyl-amino-di-phenylguanidine. pared for use in the examples as A. are herelnafter set forth byreacting phenyl-mustard pro- The thiourea desired was pared by reacting 135 parts (1 molecular This compound has been pre have manufactured and a preferably preproportion) of phenyl mustard oil with approximately 136 parts by weight (l molecular proportion) of p-amino di-methyl-aniline. The reaction that takes place Ng-oummon v is most conveniently represented as follows:

an' acid and precipitating as before with caustic. The resultlng product,- p-di-methylhas a composi-' amino-di-phenyl-guanidine, tion represented by the following formula:

The product produced as described above has been employed as an accelerator in the vulcanization of rubber comprising a 100 parts smoked sheet rubber,

5 parts zinc oxide,

3.5 parts sulphur,

0.5 parts p -di-methyl amino -di -phenylguanidine.

in a composition Such a rubber compound was manufactured in the usual manner and portions of the composition were then heated for varying tlmes in a press under the temperature given 30 paired as to be not at all practicable-for use by forty inch. The resulting products were then tested and their physical characteristics determined with the following results:

Modulus or elasticity at elongation ofm gth Ultiat mate Time of cure brat elqm 15 min. at B7 F--...- 146 293 1004 2430 835? an min. at 2879 F 210 478 1970 3100 785 min. at 287 F-. 245 549 2335 3X86 745 0 00 min. at 287' F.-. 295 734 3130 4050 755 p 31 parts smoked'sheet rubber,

. 20 parts No. 2 amber crepe rubber,

20.5 parts zinc oxide, 19 parts carbon black,

3.5 parts mineral rubber, 1 part of a blended mineral and vegetable oil v 2 parts sulphur,

. 0.5 parts p di methyl amino di phenylguanidine.

The above stock was prepared in the usual manner and portions of the composition were vulcanized by heating for different periods of time in a press maintained at the temperature given by forty pounds of steam pressure per square inch. These products were then tested and the following results were obtained:

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as c y a Ultimate Tim. 01m elongation of Tum], on! strength ti at break 5 min. at 287 F 1017 2570 3500 637% so min. at 287 F 1228 3011 3735 005 a 00 min. at 287 F 1530 3340 I 3670 545% The product was then heated in a press at approximately 287 F. and portions sotion is not to following results obtained pounds of steam pressure per square heated for varying times were tested and the The 'optimum'cureis seen to be thatiproduced after heating for approximately 45 I I minutes under the conditions set forth.

The accelerator particularly described has also been employed in the manufacture of a hard rubber composition. Such a product 2 parts p-di-methyl-amino-di-phenyl-guanidine.

The above composition was found to roduce a good hard rubber when vulcanize for about two hours and fifteen minutes in a press maintained at the temperature of approximately 287 F.

The examples hereinbefore given are 4 understood as illustrative only and not at all limitative ofthe scope of my invention. Other means of employing the preferred accelerating compound in rubber compositions,

and other means of manufacturing the particular g anidine compound described are apparent to those skilled in the art to which the invention a plies. Moreover, my invenbe understood as dependin upon the accuracy of any theories set fort way of explanation of the chemicalb clianges involved in the manufacture of the accelerator described. The invention'is to t be considered as limited solely by the following claims attached hereto as a 'part of this invention wherein I intend to claim all novelt inherent in my invention as is missib e in view of the rior art.

It is apparent from t e foregoing description that the com ounds designated as dis similar-aryl di-su stitutedguanidines hereinbefore set forth as rubber vulcanization accelerators, preferably comprise guanidine derivatives wherein different aryl groups or substituted aryl groups aresubstituted in place of two hydrogen atoms linked to two different nitrogen atoms. Such guanidines are of an entirely different type from those I obtained by replacing twohydrogen atoms perattached to the same nitrogen atom by two dissimilar groups.

I What I claim is: I mixture of rubber and sulphur in the pres- 1. The process of manufacturing vulcanence of a small proportion of an acce1eraized rubber which comprises heating a mixtor comprising p-di-methyl-amino-di-pheny1- ture of rubber and sulphur in the resence guanidine.

5 of a small proportion of p-di-methy -aminodi-phenyl-guanidine.

2. A rubber product obtained by heating a WINFIELD SCOTT.

In testimony whereof I aiiix my signature 

